title: High-performance hydrogen production and oxidation electrodes with hydrogenase supported on metallic single-wall carbon nanotube networks.
abstract: We studied the electrocatalytic activity of an [FeFe]-hydrogenase from Clostridium acetobutylicum (CaH2ase) immobilized on single-wall carbon nanotube (SWNT) networks. SWNT networks were prepared on carbon cloth by ultrasonic spraying of suspensions with predetermined ratios of metallic and semiconducting nanotubes. Current densities for both proton reduction and hydrogen oxidation electrocatalytic activities were at least 1 order of magnitude higher when hydrogenase was immobilized onto SWNT networks with high metallic tube (m-SWNT) content in comparison to hydrogenase supported on networks with low metallic tube content or when SWNTs were absent. We conclude that the increase in electrocatalytic activities in the presence of SWNTs was mainly due to the m-SWNT fraction and can be attributed to (i) substantial increases in the active electrode surface area, and (ii) improved electronic coupling between CaH2ase redox-active sites and the electrode surface.
authors.affiliation: Biosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, USA.
authors.forename: Draženka
authors.initials: D
authors.lastname: Svedružić
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Blackburn
authors.forename: Robert C
authors.initials: RC
authors.lastname: Tenent
authors.forename: John-David R
authors.initials: JD
authors.lastname: Rocha
authors.forename: Todd B
authors.initials: TB
authors.lastname: Vinzant
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Heben
authors.forename: Paul W
authors.initials: PW
authors.lastname: King
mesh_terms: D055162:Biocatalysis; D046969:Clostridium acetobutylicum / Q000201:enzymology; D004563:Electrochemistry; D004566:Electrodes; D006859:Hydrogen / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D013499:Surface Properties
chemical_list: D007506:Iron-Sulfur Proteins; D037742:Nanotubes, Carbon; D006859:Hydrogen; C118830:iron hydrogenase; D006864:Hydrogenase